Friction type clutch



March 4, 1952 C, C, DE FEW 2,587,823

FRICTION TYPE CLUTCH Filed July 16, 1946 2 SHEETS-SHEET ,l

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March 4, 1952 c. c. DE PEw 2,587,823

FRICTION TYPE CLUTCH Filed July 1e, 194e 2 sPmETs-smw z Patented Mar. 4, 1952 FRICTION TYPE CLUTCH Chester C. De Pew, Farmingdale, N. Y., assignor to Fairchild Engine and Airplane Corporation, Farmingdale, N. Y., a corporation of Maryland Application July 16, 1946, Serial No. 684,013

2 Claims. (Cl. 192-47) This invention relates to' multiple engines and has particular reference to two or more separate engines or two or more banks or groups of cylinders driving separate crankshafts, flexibly coupled together so as to jointly or severally drive a common output shaft, such as an aircraft propeller shaft, although the invention is not limited to that use.

Multiple power plants of the general class described are especially useful in the aeronautical field because of their ilexibility of operation, since best efliciency is obtained when the full power output of the plant is driving the propeller under certain conditions, whereas under other conditions best efiiciency is obtained when one or more of the engine or power units is uncoupled during flight. However, means must be provided for instant uncoupling of an engine in case of its failure. In order to reduce sources of failure a minimum amount of gearing should be employed. Means should also be provided for determining whether the power outputs of the several power plants are equal and in the ratio required by the operator. Various prior arrangements have been proposed in which one or more of the aforementioned requirements are met but none in which all of the requirements are found in a compact, light, and rugged unit providing the required sensitivity and exibility of operation.

In accordance with the present invention, a multiple engine is provided which affords the aforementioned operating requirements in a compact, light, rugged, but nevertheless sensitive form, in which a clutch is interposed between the power output shaft and the connecting gear driven by the corresponding power input shaft, each clutch being, engaged at will or automatically, and disengaged at will or automatically, in response to reduced torque or speed of the corresponding power input shaft.

In one form of the invention, two or more power input shafts are either arranged side by side in parallel relation or in endwise aligned relation with automatic coupling mechanism connected to the power input shaft and, upon initial engagement of the clutch, responsive to the torque transmitted by the corresponding power input shaft fully engaging the clutch, and equally responsive to a torque or speed input def crease for automatically disengaging the power input shaft.

In another form oi the invention, the automatic torque responsive coupling mechanism is pmitted and a fullymanual clutch control substituted, although automatic clutch control may be obtained by rendering the clutch responsive to fluid pressure dependent upon the operation of the corresponding engine, such as the pressure of an oil pump driven thereby.

For a more complete understanding of the invention, reference may be had to the accompanying drawings, in which:

Figure 1 illustrates an axial section through a multiple power plant according to this invention, in which the engines are arranged in tandem relation by way of example;

Fig. 2 illustrates a partial axial section through an automatic torque-operated form of multiple power plant unit of this invention, in which the engines are arranged in side-to-side relation; and,

Fig. 3 is a face view of one of the torqueoperated cams for actuating the automatic coupling mechanism, as seen along the line 3 3 of Fig. 2.

Referring to Fig. 1 of the drawings, numerals I0 and II designate two power input shafts arranged in tandem relation and constituting, for example, the ends of the crankshafts of two internal combustion engines individually mounted. Numeral I2 designates the long power output shaft which extends along or through the engines, and may be the shaft of an aeronautical propeller, or the like. The -coupling between each power input shaft I0 and II and the power output shaft I2 is the same so that a description of one of them will suiiice. i

The end of the power input shaft lin is journalled in a bearing I3 in the stationary frame I4 and carries a spur pinion I5 meshing with a spur gear I6 bolted at II to an annular recessed back plate I 8. Plate I8 is splined at I9 on sleeve 20, which abuts ball thrust bearing 2 I, which in turn abuts the inner race of ball bearing 22 on which that end of sleeve 20 is journalled in one-half 23- of the housing integral with frame I4. The inner race of this bearing 22 also holdsoil'slinger ring 24 in place against Spanner nut 25 threaded on the end of sleeve 20, as shown. Oil slinger ring 24 cooperates with a corresponding annular slot in cap plate 26 to prevent bleeding out of V lubricant along sleeve 2U.

The outer surface of sleeve 20 is provided with axial lsplines 21 on which spaced friction clutch discs 28 are non-rotatably slidable in an axial direction. The right-hand clutch disc 28 abuts back plate I8 and the left-hand clutch disc 28 is engaged by an annular piston 29 axially slidable in an annular cylinder 30 formed in a :flange 3| on the left-hand end of sleeve 20. The outer face of piston 29 is preferably curved so as to have a self-aligning line contact with the engaging clutch disc 23.

The clutch friction discs 32 that are interleaved with discs '28 are non-rotatably splined for axial movement on splines 33 formed on the inner surface of bell 34 whose hub 35 is splined on shaft I2 and journalled on bearings 36 and 3'I in the other half 38 of the housing, and on bearing 39 on the flange 3l of sleeve 23. The inner' race of ball bearing 36 is clamped between a shoulder 4D on hub 35 of bell 34 and a Spanner nut 4I threaded on hub 35. An intervening slinger ring 42 cooperates with anannularr recess in cap plate 43 to prevent bleeding out of lubricant along hub 35.

The annular cylinder 30 is lled with oil under pressure supplied from a source of constant oilpressure, not shown, to supply pipe 44, two: wav hand' valve 45 and feed pipe 4a. valve '4s has an "il discharge pipe46 connectible through valve diseharge passage 41 with feed pipe 48,. In vthe 'open position of valve 45, passage `49 connects supply pipe 44 with feed pipe 48, as s hfc'vviri.V Oil feed pipe 48 leads to cylinder 3l) thigh passage 50 in housing 38 to annular groove I in bearing 4U, connected by passage 52 hub 35 with annular groove 53 in bearing 39, which in turn leads by passage 5'4 in flange 3i 'to annular clutch cylinder se.

The Yother drive unit, connecting 4power input shaft vII to output shaft I2 and shown at the right of Fig'. 1 is identical to that just described. More'than twoengines may drive output shaft I'Zfarranged in tandem as shown lin Fig'. l, or two or more engines may be arranged in side-by-side relation, as shown in Fig. 2, or the like.

In operation of the multiple driving arrangement of Fig. 1, either shaft II) Vor shaft II, or b otl l may loe connected and disconnected at will toand from shaft I2 by the operator. Assuming that it is -desrifned Ato connect input shaft I0 to output shaft I2, the operator throws Avalve 45 to theM open position shown, supplying oil under pressure to'ylinder 3l to urge piston 29 to Vthe right," thusfmvforcingwclutch discsA 28 and 32 t0- getherjaether ai@ backed brplate l8 Clutch discsvZ0 and 32thusnfrictionally couple plate I8, driven frin Shefm *1y-gearing l5. ald t et@ bell 3'4...whQS.e heb 315 Splined ,l0 power 'wiper shaft I2. The drive thustakes place from Ashaft I0 through gears AI5 aand I3, plate I8, spline I3,Hsleev '2U, clutch disc 28 splined at '2"I to sleeve 420V,l clutch dises 32 splined alfl"^ 3ltoy bell 34"and bell 34 to power output shaft I2.

y "The "power input shaft II may be similarly connected to power output shaft I2, either be; fo'e or after the corresponding engine has been started, by Opening Valve 45 'to couple shaft I2 vto shaft II irl-the inanner described. The initial drive of power output shaft 'I2 by input shaft I0 in'ay be used to start the engine having shaft II, simply'by engaging the corresponde ing eluteh by jop'e'nmg valve t5'. This couples crankshaft Il` t0 rotating Shaft I2, So that when the ignition is closed, the engine connected 'to shaft II is started by the engine connected to shaft 1n. v e

[It will 'be seen that the drive from each input shaft `I0 and vII is direct and involves only one pair of gears for purposes of speed reduction, so that failure of the gearing for Vany reason lwill iifotj interrupt the drive lfrom another input sha-ft, suchas II. Also, the location lof theY clut'chbello tween the gearing I5, I6 and the output shaft ,I2 has the advantage of direct coupling.

If it is desired to disconnect the engine of shaft IIJ from shaft I2, valve 45 is rotated in the direction of the arrow, so that pressure oil supply pipe 44 is disconnected from feed pipe 48 and thevlatter is connected through valve passage 4'Irto discharge pipe 4 6. Clutch piston 30 accordingly released to disengage the 'clutch discs 23 and 32 and uncouple driving plate VI8 from bell 34 and output shaft I2. Similarly, the en- "gine of shaft II may be disconnected from output shaft I2 independently of input shaft I by manipulating valve 45 to disengage the corresponding clinch, u u

Automatic operation 0f the mechanism shown in Fig. 1- m'ay be effected by controlling the clutches in accordance with the engine operation. Thus, instead of being of constant pressure, the source of pressure oil connected to pipe 4'4 'may be an 'oil pump 56 driven directly by the engine 'driven shaft I"0, as by being geared to pinion I5. `By disconnecting the constant pres'- sur'e `source 'by closing valve '51 and opening valve 58 "and with valve 45 'openfa's shown, when the oil supply reacles a predetermined pressure 'de'- terriined by the speed o'f the engine, for 'example, clutch piston 30 is urged to the right and engages the :clutch Goni/ersely,l when the oil purhp pressure drops, ldue to Vfailure or other cause of slowing 'down of the corresponding engine, tile llitch isn/disengaged 'and the 'eg'e uneuple'd't "'reclude l s df ip'vver by being driven by an op ating engine. An independent source of o'il pressure, o' a hand pump should be supplied this ease to 'enable 'engagement of the coupling clutches when 'the erre'sponding engine is not. operating, such independent source being plaeed Vinto or out Yof luteh-opeiating conditn at y'vvll -and not interfering with the normal 'automatic operation.

u In theforrn of the "invention shown Vin Fig. 2, thecoupling of the individual 'power input shafts towtnesow'er tpt shaft is initiated autonieucally by la tolfue rs onsi've coupling mechanism." it nis d 4to start one engine from the'other or to prei/ent the propeller from over-revting as dining a glide-'fluid "is permitted to enter cylinder AIll!! 'under pressure, thereby forcing clutch plates Yand 86 into engagement and causirlgplate 11 'to e'ert'pressure upon :balls I5 at th u louc'gttlc'lin of earn ramps 14 so that torque is translni.A tvl'io'lghthe abtment's at the ends of 'the 'from `plate `I'I to cam disc 65 whereby the dfiyingand 'driven Vmembers are connestedV and the nrrn'al power linput shaft is caused to `'r't'ai'fe b'tti normal `power output shaft. Referring tolig. 2, Yvilliers the power in# pu't shafts' Y V d `6"I r-eshown in si'de-by-side relation with the output shaft 62 between them, the end If t'lje '..pwer input 'shaft 6U 'is Aprovided with aecpling'spline 53, whereby it is removablyeeuplee'ttjtnelib t4 er a 6am disc sejourq'pnbeaiing'l mounted in a 'recessed Yco'ver plate $1 lldgloy Bolts I5` 'to stationary housing `tei 'race f :bearing -is heldin place at 'I0 'secured by bolts IjI 'to cover plate e 1nne`rraceof'b1earing'66 is secured on ,by eat pl s1, a

lijns-t4 pvspanrler "mit 12. A slinger ring 1s Wenbeenngfls'andnut 1'2 andes# opera ng with l`va recess plate I1I] precludes bleedingl f lubricant over hub 64. y

' Q f' 5 'fwn lin greater detail 'in Fig- 3, ycornlz'rrlsesacl ar disc liaving-successive earn rslps n arranges eireulany en its inner face and all inclined at the same angle to a plane normal to the axis and in the same direction. Cam ramps 14 on disc 65 are adapted to cooperate with balls 15, which in turn cooperate with cam ramps 16 formed in plate 11 and conforming to cam ramps 14 but inclined in the opposite direction, as shown. Cam plate 11 is non-rotatably splined on hollow shaft 80 by splines 18 for axial movement therealong. The right-hand end of hollow shaft 80 is journalled in bearing 19 in cam plate 65, as shown. A thrust bearing 82 is interposed between the cam disc 65 and a nut 83 on the end of shaft 80. Thus, inasmuch as cam plate 65 is axially fixed, relative rotation between it and plate 11 in the direction of inclination of ramps 14, causes cam plate 11 to be moved along spline 18 to the left as seen in Fig. 2.

Shaft 80 is provided with axial splines 84, on which preferably are extensions of splines 18 and on which spaced clutch discs 85 are non-rotatably slidable in an axial direction. Interposed between clutch discs 85 are clutch discs 86 which are axially slidable but non-rotatable on splines 81 formed on the inner surface of a bell flange 88 secured to or formed integrally with hollow shaft 89 journalled at one end on bearing 90 mounted on the corresponding end of aligned shaft 8|). The other end of hollow shaft 89 is journalled in bearing 9| seated within a recess of cover plate 92 secured by bolts 93 to housing 69.

Shaft 89 is also journalled in housing 69 by ball bearing 94, whose outer race is secured to housing 69 by a ring and bolt combination 95 and whose inner race is clamped between shoulder 99 on bell ange 88 and the hub of gear 98 splined at 99 to shaft 89 and held in place thereon by spanner nut |00. Gear 98 meshes with gear |0| splined at |02 on power output shaft 62 which is journalled at one end in bearing |03 secured in a recess in housing 69 and at the other end on ball bearing |04, whose outer race is secured in cover plate 92 by ring |05 and its inner race on power output shaft 62 by spanner nut |06.`

Positioned within the chamber |08 between bell flange 88 and outer clutch disc 85 is an annular cylinder |09 formed integrally with shaft 80 and containing an axially slidable piston H0 whose outer face preferably is curved in cross-section as shown and which abuts the outer clutch disc 85. Annular cylinder |09 is normally filled with oil under pressure supplied thereto by radial passages H| leading from the cavity H2 formed jointly by hollow shafts 80 and 89 and plugs H3 and H4 held in place by bolts H5 and H6. Oil under pressure from an oil pump, not shown, is supplied through hand valve H1 to the cavity H2 by pipe H8, annulus H9 in stationary bearing 9|, and radial passage |20 leading from annulus H9 to the cavity H2. Bleed holes 2| leading from cylinder |09 prevent balls 15 from being forced to the lower ends of the cam ramps 14 and 16 during especially rigorous operating conditions, and also regulate the balance between piston |0 pressure and ball 15 pressure.

Inasmuch as the pressure on clutch discs 85 and 86 must be such asto maintain them in frictional driving engagement, it is directly proportional to the torque transmitted by input shaft 60 to output shaft 62, so that pressure on the oil in cylinder |09 when the clutch is engaged may be directly indicated by oil pressure. Accordingly a pressure-responsive torque indicator |22, such as of the Bourdon type, with its dial graduated in units of torque, is connected to oil feed line H8, as shown in Fig. 2.

The other drive unit, adapted to connect power input shaft 6| to power output shaft 62 is identical to that just described and is controlled by a hand valve H1. A torque indicator |22' indicates the torque transmitted from shaft 6| and may be juxtaposed on dial |22.

In operation of the mechanism illustrated in Figs. 2 and 3, and assuming that input shaft 60. is to be connected to power output shaft 62, the

operator throws valve H1 to the open position shown so as to connect pressure oil to cylinder |09. Piston I0 is accordingly forced to the right to the degree permitted by bleed holes 2| which are uncovered when the piston H0 reaches the predetermined position causing clutch. discs and 86 to engage suciently to hold cam plate 11 relatively xed. Inasmuch as cam plate 65 is being driven by input shaft 60 in a clockwise direction relatively to cam plate 11, which is holding the balls 15 relatively stationary, the inclination of the ramps 14 and 16 causes the balls 15 to move plate 11 to the left, as seen in Fig. 2. Plate 11 thus firmly urges clutch plates 85 and 86 into coupling engagement, whereby shafts 80 and 89 are coupled together.

The drive from power input shaft 60 takes place through spline 63, cam plate 65, balls 15, plate 11, spline 18, clutch discs 85, clutch discs 86, spline 81, bell flange 88, shaft 89, gears 98 and |0| and spline |92 to power output shaft 62. The same operation occurs between power input shaft 6| and power output shaft 62.

However, if power output shaft 62 is driven by power input shaft 6| under such conditions that put shaft 68, the balls 15 descend cam ramps 14 and 16, thus relieving the pressure on clutch i plates 85 and 86 so that the latter automatically disengage if the pressure oil supply to the corresponding clutch is cut off. It is thus evident that unless both power input shafts 60 and 6| are driving power output shaft 62 with equal speed, the one whose speed is the least will tend to become disengaged from the power output shaft 62 in the manner described.

When the speed of one declutched crankshaft equals that of the other, the corresponding clutch plates are automatically reengaged and that crankshaft coupled to power output shaft 62. Thus, by throttle and oil valve manipulation of one engine, it may be unooupled and recoupled at will from and to the power output shaft, and may operate at idling speed when not required to drive, or may be entirely stopped and then restarted in flight. Torque is indicated by oil pressure with the calibrated gauges |22 and |22 for the respective input shafts 60 and 6|, after bleed vents are closed by piston l0, when torque is directly proportional to oil pressure.

It will be seen that the automatic clutching and declutching action of the form shown in Figs. 2 and 3 is very sensitive to torque variations and also enables starting of the clutch engaging operation at will, by selective manipulation of valves H1 and H1. By connecting an oil pump, driven by the corresponding shaft 60 or 6| to the pressure supply pipes H8 and H8' the coupling may be initiated automatically instead of manually, as was described in connection with Fig. l. Thus, when the speed of crankshaft 60 reaches the point where a predetermined oil pump pressure is built up, piston H0 is advanced to the starting position where the servo ball 15 and cam 14-12 combination assumes clutching control, as described. However, for

th vari"aft-ig'ement shown in Figs. 2 and 3, a positive and constant source of fiuid pressure is prefem-ed.

Although certain preferred embodiments of the invention have been illustrated and described herein, it is to be understood that the invention is not limited thereby, o1 to coupling engine crankshafts, but is susceptible to other uses and to changes in form and detail within the scope of the appended claims.

I claim:

1.4i mechanism for driving a power output shaft from a power input shaft, comprising a first rotatably mounted plate driven by said power input shaft, a bell coaxial with said first plate and connected to said output shaft for driving the latter, an idler shaft interposed between and coaxial with lsaid plate and bell and rotatable relative to them, a clutch having opposed groups of friction clutch discs, means connecting one group fof discs to said bell for rotation therewith and axial movement relative to said bell, means connecting another group of said discs to said idler shaft for rotation therewith and axial movement relative thereto, a second plate rotatable with said idler shaft and movable axially thereof, said second plate being'interposed between said clutch and `said first plate, camming means on opposed faces of said first and second plate to move said second plate axially upon relative rotation of said plates and to couple said plates for rotation together after a predetermined relative rotation, an annular cylinder concentric with and mounted Within said bell for rotation therewith, an annular piston in said cylinder adjacent to and engageable with one of the clutch discs, and means for introducing fiuid under pressure into said cylinderv to urge said piston against said one of said clutch discs to force said discs together and against said second plate to rotate the latter relative to .said rst plate, said camming means then becoming effective to couple said first plate to said second plate.

2. .A mechanism for driving a power output shaft from Va power input shaft, comprising a first rotatably mounted plate driven by said input shaft, a bell coaxial with said firstplate and connected to said output shaft for driving the latter, opposed friction clutch discs, means connecting at least one of said discs to said bell for rotation therewith, a second plate adjacent to said first plate and between said rst plate and said clutch discs and coaxial therewith, means connecting another of said discs to said vsecond plate for rotation therewith, camming means on opposed faces of l'said first and second plates to move said second plate axially upon relative rotation of said first and second plates and to couple .said plates for' rotation together after a predetermined relative rotation, an annular cylinder concentric Wth and mounted within said bell for rotation therewith, an annular piston in said cylinder adjacent to and engageable With one of the clutch discs, and means for introducing fiuid under pressure into said cylinder to urge said piston against said one of said clutch discs to force said discs together and against said second plate to rotate the latter relative to said first plate, said camming means then becoming effective to'couple said first plate to said second plate.

CHESTER C. DE PEW.

REFERENCES CITED The .following references are of record in the ,le ,of this patent:

UNITED STATES PATENTS Number Name Date 2,014,630 OBrien Sept. 17, 1935 2,020,667 Wahl NOV. 12, 1935 2,091,270 Colman Aug. 3l, 1937 2,239,236 Lambert Apr. 22, 1941 27,314,030 Bloomfield Mar. 13, 1943 2,408,301 Eason Sept. 24, 1946 2,448,763 Bloomeld Sept. 7, 1948 

